Various weight selection methods and apparatus have been developed to provide adjustable resistance to exercise. With respect to free weights, weight plates are typically mounted on opposite ends of a bar. In relatively advanced systems, the bar or handle assembly is stored in proximity to the weight plates, and at least one selection mechanism is provided to connect a desired amount of mass to the bar.
Some examples of patented barbell/dumbbell improvements and/or features are disclosed in U.S. Pat. No. 4,529,198 to Hettick, Jr. (discloses a barbell assembly having opposite end weights that are maintained in alignment on respective storage members and selectively connected to a handle by means of axially movable springs); U.S. Pat. No. 4,822,034 to Shields (discloses both barbell and dumbbell assemblies having opposite end weights that are maintained in alignment on a shelf and selectively connected to a handle by means of latches on the weights); U.S. Pat. No. 5,284,463 to Shields (discloses a dumbbell assembly having opposite end weights that are maintained in alignment on a base and selectively connected to a handle by means of cam driven pins on the weights); U.S. Pat. No. 5,637,064 to Olson et al. (discloses a dumbbell assembly having a plurality of interconnected opposite end weights that are stored in nested relationship to one another and selectively connected to a handle by means of a U-shaped pin); U.S. Pat. No. 5,769,762 to Towley, III et al. (discloses a dumbbell assembly having a plurality of interconnected opposite end weights that are stored in nested relationship to one another and selectively connected to a handle by various means); U.S. Pat. No. 5,839,997 to Roth et al. (discloses a dumbbell assembly having opposite end weights that are maintained in alignment on a base and selectively connected to a handle by means of eccentric cams on a rotating selector rod); and U.S. Pat. No. 6,033,350 to Krull (discloses a dumbbell assembly having opposite end weights that are maintained in alignment on a base and selectively connected to a handle by means of respective first and second selector rods that move axially in opposite directions). Despite these advances and others in the field of weight selection, room for improvement and continued innovation remains.